Seal-Scan

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• Seal-Scan
• Non-Destructive Inspection Technology
• for Retort Pouches
• Tony Stauffer
• Packaging Technologies Inspection
• Tuckahoe, New York
• PTI Inspection Systems www.ptiusa.com
• 800.532.1501
• Pti_at_ptiusa.com

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Seal-Scan

• Only Seal Inspection system that is
• Non-destructive
• Non-invasive
• Non-contact

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Applications of Seal-Scan Ultrasound Inspection

• Analyzes seal quality of pouches and flexible
  packages
• Characterizes bonded materials
• Works with all materials film, alu, paper, or
  composite
• Process control
• Quality control
• Research and development

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Seal-Scan

• Produces a single linear scan in less than 1
  second
• Digital pouch seal image in less than one minute
• Images and characterizes bonded materials
• Helps in process optimization

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Seal-Scan Principle of Through Transmission
Ultrasonic Signal
SEAL
Transmitter
Receiver
Pouch seal or package material is placed between ultrasonic transmitter and receiver
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Ultrasonic Signal

• Ultrasonic waves propagate through single or
  multiple layers of well bonded materials.
• Transition through different mediums causes
  reflection of sound waves and reduces/eliminates
  signal strength.

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Seal-Scan Technology
Ultrasonic signal is transmitted along the X-axis through seal and signal is recorded.
Signal measurement correlates to color gauge, creating high resolution image of seal structure and quality.
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Seal-Scan Signal Scale Opto Acoustic Image

• The colored gauge represents the scan signal
  measurement.
• Pink is low signal, green is normal signal (good
  seal), purple is high signal.
• Total 6000 grades of color are used.

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Scanning Modes

• L-Scan produces a graph of the signal and
  summary data.

• C-Scan produces an Opto-Acoustic image
  
• and summary data

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Pass Fail Criteria and Data Integrity
Pass Fail limits are set for the average,
minimum, maximum, and standard deviation of the
signal measurements, All results are recorded
using the systems data log.
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Seal-Scan 525 Offline Analytical Equipment
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C-Scan Analytical Tools
C-Scan window statistics
Modified L-Scan
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C-Scan Analytical Tools
C-Scan statistics of moving window
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Optimizing the Sealing Process
Seal-Scan serves as an analytical tool to
determine optimal sealing conditions e.g.
temperature, dwell time, etc.
Variation decreases with increasing temperature.
Optimal Sealing Temperature
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Material Analysis





HDPE exhibits better sealing uniformity and
quality at higher temperatures. TYVEK exhibited
weaker bonding at higher temperatures.
105 C HDPE 105 C HDPE 105 C
HDPE 105 C HDPE 105 C HDPE




128 C HDPE 128 C HDPE 128 C
HDPE 128 C HDPE 128 C HDPE



108 C TYVEK 108 C TYVEK 108 C
TYVEK 108 C TYVEK 108 C TYVEK






134 C TYVEK 134 C TYVEK 134 C
TYVEK 134 C TYVEK 134 C TYVEK
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Seal-Scan and Peel Strength Testing

• Background
• Pouches with peelable seals were tested.
• Peel strength test was performed on specific area
  of seal sample, approximately one-inch.
• Seal-Scan C-Scan mode analysis of entire length
  of seal was performed.
• Results confirm direct correlation of both
  methods.

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Seal-Scan and Peel Strength Testing
The Standard Deviation of the ultrasound signal
correlates to the peel strength of a peelable
seal. Seals with more variation in the quality
of a sealed area will be easier to peel than a
seal area that is uniform. If a seal has strong
points of bonding but exhibits high variation,
the peel strength of the seal will be less.
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Good Seal Profile(Film-Pouch)
C-Scan
Seal Quality Histogram
Seal width profile
Seal Width Data, mm
L-Scan
L-Scan Statistics, Signal Value
Test results to be compared against Pass-Fail
reference values.

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Defective Seal Profile (Alu-Pouch Channel Leak)
C-Scan
Seal Quality Histogram
Seal width profile
Seal Width Data, mm
L-Scan
L-Scan Statistics, Signal Value
Low average and minimum, with high standard
deviation.
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Case Study Heinz Douarnenex, Fr

• Defect Profile - 30,000 pouches were visually
  inspected 100

Defect type Comment Number detected Reject Rate
Leak Critical 3 .01
Corner channel Major or critical 4 .01
Wrinkle Depends on height 8 .03
Inclusion Depends on height 4 .01
Air bubbles Depends on size 19 .06
Waves Usually minor 12 .04
Blister Minor 86 .29
Fold Minor 11 .04
Total defects 147 .49
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Case Study Heinz Douarnenex, FrTypical Defects
Leak
Critical
Corner Channel
Critical
Critical (may vary)
Wrinkle

Minor
Inclusion
Critical
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Case Study Heinz Douarnenex, FrTypical Defects
Air Bubbles
Critical
Critical
Minor

Waves
Critical
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PTI-550 Online Pouch Inspection

• Pouches go onto Seal-Scan from pouch machine at
  60-70/Minute

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PTI-550 Online Pouch Inspection

• 1. Pouches are dropped into a special conveyor
• 2. Pass through PTI Seal-Scan Ultrasonic-head
• 3. Accepted or rejected

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PTI-550 Online Pouch Inspection
Pouch Seal is guided through the Seal-Scan Head

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PTI-550 Online Pouch Inspection

• Seal-Scan Head with Operator interface

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PTI-550 Online Pouch Inspection

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Packaging Technologies Inspection

• Seal-Scan 525
• Defect Gallery

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Channel

• Description
• An area of non-bonding across the seal that will
  generally leak
• Cause
• Sealing bar settings were not correctly set
  (temperature, pressure and/or
• dwell time.)
• Contaminants may be present during seal
  formation.

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Compressed Seal

• Description
• Any separation of laminates in seal area.
  Material bond strength is
• questionable in defect area. Visual evidence
  of overheating such as
• bubbles.
• Cause
• Sealing bars were too hot during seal formation.
  
• Material bond strength is inadequate.

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Contamination

• Description
• Foreign material is trapped in seal. Retort
  pouches will have noticeable
• raised areas in seal where sealing bar sealed
  over contamination.
• Cause
• Seal area was contaminated during filling stage.

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Crooked Seal

• Description
• A seal that is not parallel to the cut edge of
  the pouch
• Cause
• Pouch was misaligned in the sealing jaws.

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Cut

• Description
• A breach of all layers of the laminate, where
  the hermetic integrity of the
• package was compromised.
• Cause
• Equipment damage or scrap between laminate
  plies during formation.
• Pouch contacted sharp edges of other pouches or
  equipment.
• Pouches were abused during online or
  post-process handling.

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Delamination

• Description
• Separation of laminated materials can occur
  before or after retort
• process. Delaminations ultimately affect seal
  strength through life
• cycle/distribution process.
• Cause
• If occurring at the seal, bars were too hot
  during seal formation.
• If during retort process, residual air in the
  pouch was not controlled to
• eliminate pouch expansion during retorting.

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Incomplete Seal

• Description
• Seal area does not extend completely across the
  width of pouch.
• Cause
• Pouch was not positioned correctly in sealer and
  sealing bar.

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Narrow Seal

• Description
• Container seal area has no margin of safety to
  accommodate seal creep
• or wrinkles.
• Cause
• Defective sealing bars reduced seal width.
• Defects that cross seal, seal creep or
  mechanical separation reduce seal
• width.

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Non-Bonding Seal

• Description
• Sealing films fail to weld during sealing
  process. Defect appears as faint
• sealing bar impression on retort seals.
  Application of slight pressure to
• seal will cause failure.
• Cause
• Seal area was contaminated.
• Sealing bar settings were not correct
  (pressure/temperature/dwell time).

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Wrinkle

• Description
• Material fold on one seal surface, caused when
  one seal surface is longer
• than the other. Can also be a severe fold over
  both seal surfaces at
• sealing time.
• Cause
• Sealing surfaces were not flat and parallel or
  were not tensioned.
• Various other irregularities in sealing bar or
  surfaces.

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Pouch Inspection Economics

• One technology useable for all materials
• Non-Destructive, Non-Invasive
• No sample preparation,
• No special Inks, no added variable costs
• Replaces costly, low efficiency manual Inspection
• Reduces/eliminates Incubation
• Saves product packages
• Long term quality tracking
• Integrates into most pouch sealing machines
• Real Time Process Control - allows immediate
  corrective action
• Increases line efficiency
• Good return on investment
• You sleep better at night

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Thank You